Daenaerys Targaryen’s dragons are going to be a game changer in the final stretch of Game of Thrones, and it might not be for the reason you think.

In previous seasons, she’s used her dragons against hostile armies filled with random extras (see: the Sons of the Harpy). But the seventh and penultimate season, which will finally see her in Westeros, will be the first time she uses them against characters we know and care about — like Jaime and Bronn. There’s also another more intriguing reason her dragons will shake up the show in Season 7, and it involves ice dragons.

Rumors and theories abound that ice dragons could make their onscreen debut in Game of Thrones Season 7.

Since it’s the second to last season, their presence would certainly up the ante. But what’s behind these rumors and what do you need to know? Here’s your ice dragon tutorial.

Sam and Gilly research in 'Game of Thrones' Season 7
Sam and Gilly research in 'Game of Thrones' Season 7

1. A photo of Sam hints that they could be in Season 7

At the end of Season 6, Sam and Gilly arrived at the Citadel, which is essentially Masters HQ. In Season 7, they’ll be beefing up on plot-relevant knowledge thanks to its massive libraries. One photo from the season shows them reading about Azor Ahai, a legendary hero from long ago who will supposedly be reborn to save the world from darkness.

That’s the part that has caught everyone’s attention, since many fans think Jon Snow is Azor Ahai reborn. But elsewhere in Sam and Gilly’s reading material, there’s also a reference to ice spiders.

2. It all goes back to Old Nan

When the Stark children and Jon Snow were growing up at Winterfell, Old Nan told them stories filled with mythical creatures. Ice spiders are one such myth. But many people also think White Walkers are legendary, and look how that turned out. If Sam and Gilly’s reading material implies that ice spiders will appear, it also paves the way for ice dragons. Although they haven’t been mentioned in the show, they come up in the books.

In A Dance With Dragons Jon Snow stops to reflect on Old Nan’s stories: “The wind was gusting, cold as the breath of the ice dragon in the tales Old Nan had told when Jon was a boy.”

3. Martin was thinking about them even before he wrote A Song of Ice and Fire

George R.R. Martin has been thinking about ice dragons for over twenty years. Even before he wrote A Song of Ice and Fire, he wrote a 1980 children’s book aptly named The Ice Dragon. In the story, a little girl bonds with an ice dragon and it subsequently aids her in defeating fire dragons. Hmmm.

4. They might be even more dangerous than normal dragons

As Martin describes in The Ice Dragon, they breath ice that’s as deadly as fire:

Ice formed when it breathed. Warmth fled. Fires guttered and went out, shriven by the chill. Trees froze through to their slow secret souls, and their limbs turned brittle and cracked from their own weight. Animals turned blue and whimpered and died, their eyes bulging and their skin covered over with frost. The ice dragon breathed death into the world; death and quiet and cold.

If they were to appear on Game of Thrones, they might wreak even more havoc than Dany’s normal dragons.

Until Season 7 airs, it’s impossible to say if ice spiders and ice dragons will make their onscreen debut. But if if the show does intend to include them, the season gearing up for the final act would be the time. If it’s a song of ice and fire, you might as well have dragons breathing both.

Game of Thrones Season 7 premieres July 16 on HBO.

Photos via HBO